I find in these cases that the criticisms are typically very valid and even in the cases that I disagree on the overall consensus, I agree on with a lot of the negative aspects of their argument. Unfortunately, once a game hits a certain tipping point, it's difficult to discuss the positive aspects at all because the conversation is always funneled in one direction.
I have no dog in this fight, actually. I haven't played MGSV and I have little interest in doing so. The series kind of lost me on MGS3, when the whole gameplay simply became too tedious for me to care.
And I agree with you. What I find taxing on GAF is when you like a game that the vocal majority has often condemned, any mention of it will be drowned out by many simply trashing the game in drivebys full of hyperbole.
For instance, I personally love SWTOR and Dragon Age Inquisition, and although I acknowledge that they are flawed, there is little reason in talking about these games because I know I'll be dogpiled.
Sadly, I myself have been part of the problem because lord knows that I spent far too much time on GAF jumping down the throat of any person who expressed admiration for Mass Effect 2 or Dragon Age 2.
However, I've mellowed and accepted that people like what people like. It's how I can now stand to read discussion of Fallout 4 on here, although I am weary of constantly reading about how it's going to be a terrible game.
_/¯